1900.] INSECTS OF THE “ SKEAT EXPEDITION.” 857 
centre and not towards the periphery; but, nevertheless, it was 
striking and, at a first glance, quite deceptive. When disturbed 
the caterpillar commenced to walk along the leaf, slowly and 
irresolutely, unbending and rebending its long thoracic limbs as 
it moved, and shaking the two processes with which its abdomen 
terminated. I took it home, and shut it up till the next morning 
with a supply of leaves, hoping to photograph it when the light 
was better. During the night the insect cast its skin, and in the 
morning all likeness to anything else had left it. The skin was 
no longer polished and glittering, and the colour had changed to 
a dull brown with dingy white bars. Moreover, all sluggishness 
of movement had disappeared, and the caterpillar was now ex- 
ceedingly brisk, behaving very much as a well-grown specimen of 
our own English form would do. During the languor and 
dangerous inactivity of the ecdysis and the period immediately 
preceding it, protective coloration had been assumed ; as soon as 
the operation had been safely performed, the habitual means of 
defence were adopted once more. 
But to return to animals which, being otherwise inconspicuous, 
have the power of exhibiting brilliant colour when alarmed. This 
phenomenon is not only exemplified by insects. A good instance 
is that of the Toad Callula pulchra, which is found not un- 
commonly in the Siamese States, among the rubbish which collects 
under the houses and in hke situations. In this species, the upper 
surface of which is otherwise of a warm brown colour, a broad 
yellowish stripe runs along either side of the back; but the 
peculiar looseness of the skin and the folds into which it naturally 
falls prevent this stripe from becoming conspicuous. When the 
animal is disturbed, however, it draws air into its lungs until its 
body becomes almost globular, and the skin is stretched in such 
a way that its contrasting colours are displayed to their best 
advantage. We may compare this amphibian to the fish of the 
genus Yetrodon and others, which have earned the name of 
Balloon-fish among Europeans, and of “ /kan buntal,” or Pillow-fish, 
among Malays, by the manner in which they gulp down air into 
their stomachs, so causing the brilliant coloration of many of 
them to become conspicuous, and also the spines with which they 
are armed to be erected. 
Another interesting example is afforded by the Lizard Liolepis 
bella, which the Malays call ‘ Biawak Pasir” *, or Sand Monitor, 
and which is common in all sandy plains where the vegetation is 
scanty in the north of the Malay Peninsula. The male of Liolepis 
is coloured in what sounds a very gorgeous fashion, and what is 
in nature by no means a conspicuous one. The upper surface is 
grey, mottled and eyed with green, the lower surface pale yellow 
veined with blue, which is more conspicuous on the underside of 
the thighs and the neck than on the rest of the body. Along each 
side there are a number of transverse bars, alternately of orange 
1 « Biawak” is the Malay name of Varanus. 
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